There are three general types of maintenance for products. They are on-demand maintenance (usually when a product breaks), scheduled maintenance (based upon the best estimate of a manufacturer as to when something will wear out with normal usage), and condition based maintenance (maintenance that occurs when maximum usage is obtained from a part but just prior to part failure). On demand maintenance is self-explanatory. It is when a component fails and has to be repaired or replaced. This normally occurs as an end result of its operators not understanding its component life or the conditions of its use, and the highest costs, both physical and lost time, are associated with it. Unfortunately, it is also one of the most common types of maintenance. Scheduled maintenance is less costly but can be very wasteful. Depending upon the usage of a product, one may be replacing parts that still have a significantly useful life. This is also where corners tend to be cut by the customer when budgets become tight, and often leads back to the first type of maintenance described above. The third form of maintenance is condition-based maintenance and is the holy grail of maintenance in many industries. If a manufacturer or service organization can accurately ascertain the maximum life of a component based upon actual wear, tear, and usage, it could then allow for the optimized, just-in-time servicing and replacement of that component, thereby allowing for the user to gain maximum product life and to schedule the replacement at a non-critical time. As a result, a manufacturer utilizing condition based maintenance could better plan its spares production and save millions of dollars in unnecessary production, warehousing and inventory taxes.
There is however a catch to condition-based maintenance. A closed feedback loop system of information related to the use of each product must be provided. Without first-hand knowledge of how a product is being used after it is sold and deployed to the field, a manufacturer or service provider has no real way of knowing when components will wear out based on usage, and must therefore default back to using one or both of the first two types of maintenance described above. Operators are in the best position to gather this first hand knowledge, but most are too busy operating and making money with the product and have little time, money and/or inclination to attempt to capture this information to provide feedback to the manufacturer or service provider, even though it is in their own best interest to do so.
In an attempt to gather useful information from the field, a variety of methods have been used to try and solve the collection of product usage data. On the low end, customer surveys, feedback forms, and interaction with field support personnel have been the primary means of obtaining a rudimentary form of feedback. For complex and expensive products, such as aircraft engines, the most common form is that of paper-based operational logs. This is a highly manual and painful method of collecting operational information. Over the years, computer collection systems have tried to make this process easier, but they still require a great deal of manual intervention.
More recent advances have involved the incorporation of automated data recording devices onto products, such as engine data units (or EDUs), which are used on turbine engines, and which communicate with electronic engine control (EEC) systems and record operational data using a variety of sensors. However, it is still extremely difficult and costly to gather information from these data collection devices, as it must be done manually by mechanics in the field using specialized equipment or laptop computers temporarily cabled to the EDU or EEC, and with which they usually have little familiarity or interest. The only other option is to wait until the product is returned to a shop environment for a major overhaul and repair, at which point the data from a preventative maintenance perspective is moot, and useful only from a post analysis or fleet average perspective.
A number of industries normally attempt to gather product usage intelligence through manual inspections and, more recently, laptop computer downloads performed concurrently with scheduled or on-demand maintenance service calls. This is normally accomplished by one or two methods: sending a service person to the product, bringing the product to a service center, or both. Examples of the former include products with fixed installations, such as elevators, HVAC systems, nuclear power plants and large home appliances. Examples of the latter include automobiles, small home appliances, home electronics equipment, lawn-mowers, or anything small enough to be easily carried or shipped. Both methods are inefficient and result in significant down time.
With advances in low cost computing and the advent of wireless technologies and the Internet, companies are now looking at how they can collect product usage intelligence in an automated and remote fashion. Many of the systems which have evolved, such as VHF frequency, cell phone, or wireless land-based data download methods, tend to be very expensive as have attempts at using emerging technologies to accomplish essentially the same thing, i.e., using remote data file compression and download to a central location using a public or private network/Internet where the information can then be manually uncompressed and analyzed. As a result, the high cost associated with such methods restricts the application of wireless remote monitoring to high value products, such as jet aircraft and helicopters. Thus, there remains a need for a low cost, wireless system which accurately ascertains the condition of a deployed product based upon actual wear, tear, and usage and presents information about that condition to a user, a manufacturer, an operator, or any other interested party, that is deployable with the product and that provides greater flexibility and interaction than simple data downloading.
Moreover, in certain applications, such as aircraft engines, it may be desirable to wirelessly download engine data to a remote location, but not allow the remote location to gain access to all of the propriety algorithms, data, or software being utilized by the engine. Accordingly, a need exits for wireless system for communicating with a deployed product, wherein only certain information is accessible from the remote location.